Re: colorbar for decimal images

[Lorenzo Trojan]

On Oct 30, 2009, at 7:54 AM, Lorenzo Trojan <address@hidden>  
wrote:

> > Hi all,
> >
> > sorry for asking this question, I've been looking around but I  
> > couldn't find a solution to this.
> >
> > I have a matrix of intensities. The intensity of each pixel is a  
> > double number ranging from e-4 to e-3 and I'd like to produce an  
> > image using image() or imshow() and add a colorbar showing the  
> > correct range of values. I could do something like:
> >
> > > minmat = min (min (matrix)) ;
> > > maxmat = max (max (matrix)) ;
> > > delmat = maxmat - minmat ;
> > > imgmat = (matrix + minmat) * 64 / delmat ;
> > > image (imgmat);
> > > colormat (hot (64)) ;
> > > colorbar ();
> >
> > but then the colorbar would show the range from 1 to 64.
> >
> > is there a way to change the labels to the colorbar so that it  
> > display the range of the original image limits? I tried to look for  
> > the axis object associated with the colorbar, but I could't find  
> > them...
> 
> You can obtain the handle to the colorbar by
> 
> hc = findall (gcf, "tag", "colorbar", "type", "axes");
> 
> Or when you create the colorbar ...
> 
> hc = colorbar ();
> 
> Ben

Hi

Thanks for the reply. I downloaded findall which didn't seem to be installed on 
my system, from:

http://velveeta.che.wisc.edu/cgi-bin/hgwebdir.cgi/octave/file/tip//scripts/plot/findall.m?rev=HEAD&content-type=text/plain

but is didn't work. When i use it says:

> warning: get: invalid property `showhiddenhandles'

and a bunch of other errors. the second solution also didn't work. Octave 
returns:

> error: value on right hand side of assignment is undefined

I've installed octave from the main Ubuntu rep:

> octave:1405> version 
> ans = 3.0.1

is this octave version too old?

thanks
Lorenzo